LeetCode: Insertion Sort List

class Solution {
public:
ListNode *insertionSortList(ListNode *head) {
ListNode* sortedHead = new ListNode(0);
while (head){
ListNode* cur = sortedHead;
ListNode* tmp = head->next;
while (cur->next != NULL && cur->next->val < head->val){
cur = cur->next;
}
head->next = cur->next;
cur->next = head;
head = tmp;
}
return sortedHead->next;
}
};